content Flashcards
Wedge
Wedges are very basic simple machines that are made up of two inclined planes placed back to back. Wedges can be used to cut, split, tighten, hold things together, and scrape things.
Wheel and Axle
A wheel and axle is made up of a larger disc attached in the centre to a smaller cylinder. Axles and wheels by themselves are not simple machines—only the combination of the two make a simple machine. The circular disc of the wheel acts as a class 1 lever with the axle as the fulcrum. Turning the wheel (the input force) causes that axle to turn (the output force).
Lever
A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum.
Inclined Plane
An inclined plane is a sloped surface that reduces the effort needed to move an object by spreading the required force over a longer distance. While the object is moved a greater distance compared to lifting it directly, the force required is less. This helps make the task of moving objects easier, but the total amount of work remains the same.
Screw
A screw is an inclined plane that is wrapped around a cylinder that converts a rotational force to a linear force.
Pulley
A pulley is a wheel used in a different way. A pulley consists of a rope and hub or ‘drum’ in which there is a grooved wheel mounted with an axle.
Examples of Wedge
Axes
Knives
Screwdrivers
Examples of Wheel and Axle
Bicycle
Car
Hand Truck
Wagon
Examples of Inclined Plane
Ramp, hill
Examples of Screw
Wood Screws
Machine Screws
Sheet Metal Screws
Examples of Pulley
Fixed, moveable, compound, and complex
Explain the concept of work in relation to simple machines
When a force acts upon an object to cause a displacement of the object, it is said that work was done upon the object.
Define Mechanical advantage
Mechanical advantage (MA) is a measure of how much a machine amplifies the input force to perform a task. It is defined as the ratio of the output force exerted by the machine to the input force applied to it. In other words, it tells you how much easier a machine makes it to move a load or perform work.
Define power
Power (P) is the rate at which work is done per unit time
Explain the relationship between work done, mechanical energy, and power.
Work and Mechanical Energy: Work done alters mechanical energy.
Work and Power: Power is the rate of doing work.
Mechanical Energy and Power: Power measures how quickly mechanical energy changes.
Explain the relationship between mechanical advantage and effort required
The mechanical advantage of a machine indicates how effectively it amplifies the applied force. A higher mechanical advantage means less effort is needed to perform a task, though it may require moving the load over a greater distance.
Define velocity ratio.
the ratio of a distance through which any part of a machine moves to that which the driving part moves during the same time (VR = DE / DL)
Compare and contrast velocity ratio and mechanical advantage
VR relates to speed, while MA relates to force.
Both are ratios, but VR deals with motion and MA with power output.
VR is theoretical, while MA reflects actual performance, influenced by friction and efficiency.
Define efficiency and its significance in mechanical systems
Efficiency in mechanical systems is the measure of how effectively a machine converts input energy into useful output energy.
Discuss factors affecting efficiency
Friction, materials quality, design of equipment, maintenance
Define gear ratio and its relevance in gear systems
Gear Ratio is the ratio of the number of teeth on two interlocking gears or the ratio of their rotational speeds. It determines how torque and speed are transferred between gears in a gear system.
If the driver gear is larger than the driven gear, is it a speed multiplier or force multiplier
Increase speed decrease torque
If the driven gear is larger than the driver gear, is it a speed multiplier or force multiplier
Increase torque decrease speed
VR formula for worm gear
teeth on worm gear / threading of worm wheel
Provide examples and practical applications of spur gears
Gearbox in Vehicles: Transfers power between shafts to control speed and torque.
Clock Mechanisms: Drives the movement of clock hands with precise timekeeping.
Industrial Conveyors: Moves conveyor belts and machinery components.
Washing Machines: Powers the drum and agitator for washing clothes.
3D Printers: Controls the movement of the print head and build platform.
Toy Cars: Transfers rotational motion from the motor to the wheels for movement.
Explain the principle of operation of worm gears
A gear consisting of a shaft with a spiral thread that engages with and drives a toothed wheel. Worm gears are used to transmit power between two shafts that are at right angles to each other and are non-intersecting.
This results in significant speed reduction and increased torque. Their self-locking design prevents the worm wheel from driving the worm, making them ideal for applications requiring a secure, non-reversible mechanism.
Advantages of worm gear
High speed reduction
Compact design
Transmit power between non-intersecting shafts
Self-locking (no back-driving)
Identify practical applications of worm gears
Automotive Steering: Provides precise steering control.
Winches: Converts high-speed input to high-torque output.
Fishing Reel: Provides smooth line retrieval and precise drag control.
Guitar Tuning: Allows fine adjustments to string tension for precise pitch control.
Explain the conversion of rotational motion to linear motion in rack and pinion systems
The pinion gear rotates and meshes with the rack, causing the rack to be driven in a straight line.
Identify common uses of rack and pinion systems
Steering Systems in Vehicles, Printers, CNC machines
What is a bevel gear
A bevel gear is a type of gear designed to transmit motion and torque between shafts that are at an angle to each other, typically at a 90-degree angle. Bevel gears have conical-shaped teeth that mesh with each other, allowing for the transfer of rotational motion and force between intersecting shafts.
Provide examples and practical applications of bevel gears
Automobile Differentials: Allow wheels to rotate at different speeds.
Hand Drill
VR in wheel and axle
2πR (wheel) / 2πr (axle)
VR in inclined planes
1 / sin(θ)
What is the distance the load moves in inclined planes
the height of the inclined plane
VR in screws
Circumference (2πr or πd) / pitch
VR in pulleys
Number of rope sections supporting the load
How to calculate output speed
output = input / VR
VR / gear ratio in gears
(Radius, Diameter, Circumference, #teeth) of driven / (Radius, Diameter, Circumference, #teeth) of driver
Types of motion
Rotary, Linear, Reciprocating, Oscillating
What is the advantage of a simple machine
It makes work easier by either changing direction, increasing magnitude, increasing the distance or speed of a force or transferring the force from one place to another
What is purpose of first class lever
The purpose of a first-class lever is to amplify force and change the direction of applied force. In a first-class lever, the fulcrum (pivot point) is positioned between the input force and the load.
What is purpose of second class lever
The purpose of a second-class lever is to increase the mechanical advantage, allowing a smaller effort to lift or move a larger load. In a second-class lever, the load is positioned between the fulcrum and the effort.
What is purpose of third class lever
The purpose of a third-class lever is to increase the speed and range of motion of a load rather than to amplify force. In a third-class lever, the effort is applied between the fulcrum and the load.
What is a gear
A gear is a rotating machine part used to transmit rotational motion and/or torque by means of a series of teeth that engage with compatible teeth of another gear or other part.
Prevents slippage and the change of speed, torque and rotational direction
Importance of efficiency,
Cost Savings, performance enhancement, extend equipment life
Examples of first class lever
Seesaw
Crowbar
Pry Bar
Examples of second class lever
Wheelbarrow
Nutcracker
Bottle Opener
Examples of third class lever
Tweezers
Fishing Rod
Broom
Ideal MA of First class lever
If the fulcrum is closer to the load, the lever has a mechanical advantage (MA) greater than 1. If the fulcrum is in the middle, MA equals 1.
Ideal MA of Second class lever
Greater than 1
Ideal MA of Third class lever
Less than 1
Are First class levers force multipliers or speed multipliers
Force Multiplier
Are Second class levers force multipliers or speed multipliers
Force Multiplier
Are Third class levers force multipliers or speed multipliers
Speed Multiplier
A wheel and axle belongs to what type of fundamental simple machine?
Lever
A screw belongs to what type of fundamental simple machine?
inclined plane
What is mechanical energy
Mechanical energy is the sum of kinetic and potential energy within a physical system.
